1. Field of the Invention
The present invention generally relates to a RFID device having a nonvolatile ferroelectric capacitor, and more specifically, to a technology of reducing the whole size of a RFID device using a nonvolatile ferroelectric capacitor formed by the same process as that of a memory cell capacitor.
2. Description of the Related Art
Generally, a ferroelectric random access memory (hereinafter, referred to as ‘FeRAM’) has attracted considerable attention as next generation memory device because it has a data processing speed as fast as a Dynamic Random Access Memory (hereinafter, referred to as ‘DRAM’) and preserves data even after the power is turned off.
The FeRAM having structures similar to the DRAM includes the capacitors made of a ferroelectric substance, so that it utilizes the high residual polarization characteristic of the ferroelectric substance in which data is not deleted even after an electric field is eliminated.
Meanwhile, a general Radio Frequency Identification device (hereinafter, referred to as “RFID”) comprises a modulator and a demodulator for modulating and demodulating a radio frequency signal and a voltage multiplier for generating a power voltage.
A conventional capacitor used in the voltage multiplier, the modulator and the demodulator has a PIP (Poly-Insulator-Poly) structure. Preferably, an insulator is SiO2 or Al2O3 which is an upper dielectric material.
However, since the above-described upper dielectric materials have a small dielectric constant, a large number of capacitors are used to obtain desired capacitance. As a result, the whole chip area is increased.
The conventional capacitor used in the voltage multiplier, the modulator and the demodulator is formed by a different process than that of a cell capacitor of a memory. Thus, rendering the fabrication process increasingly complicated and costly.